Determine the weight of a body.

Principle: When a spring is fixed at one end and a force is applied to the other end the stretching of the spring is proportional to the applied force". provided the force is within the elastic limit of the spring 

Apparatus: An extensible spring, pan, pin, weights, retort stand, metre scale, plasticine. within the elastic limit of the spring

Apparatus: An extensible spring, pan, pin, weights, retort stand, metre scale, plasticine.

PROCEDURE

• Suspend the extensible spring from a suitable stand with a hook Attach a pan to the lower end of the spring.
• Also fix a pin at the lower end and at right angles to the spring by means of a little plasticine
• The horizontal pin serves as a pointer 
• Fix the metre scale vertically so that the pin (pointer) can move over the scale
• This arrangement shown in Fig. serves as a spring balance.
• Record the reading of the pointer on the scale (l₀) initially.
• Add 10 gram weight to the scale pan.
• Note the reading of the pointer (l₁)
• Proceed like this increasing loads regularly in steps of 10 grams upto about 100 grams.
• Record the values of l₁ in each case.
• Take second set of readings while the pan is gradually unloaded in the same regular steps .
• Enter the readings (l₂) in the table shown and calculate the mean - extension.